networking basics

Networking Basics

Think Time

Think Time

What is common to all these?

Types of Communication

Unicast is one to one communication


Multicast is one to group communication


Broadcast is one to all communication


Similarly we have three ways of transmitting data.

They are,

– Simplex

• Refers to transmission in only one direction where one party

is the transmitter and the other is the receiver

– Half duplex

• Refers to two-way communications where only one party can

transmit at a time

– Full duplex

• Refers to the transmission of data in two directions

simultaneously.

Think Time

OS

Hardware

???Fully operational

system

Why Networking?

– Resource sharing

– Data sharing

– Performing complex operations by

distributing the work

– Accessing remote data and devices

– Interacting with other computers

– Accessing applications such as the World

Wide Web

Computers maybe networked for one or more of the following reasons –

Basically, means

that 2 or more

computers

communicate!

Think Time

Shall we define what a Computer Network is?

A group of two or more computer systems that are linked together,

form, what is called a computer network

Computers on networks are sometimes called nodes

– A node is a processing location in a network

– It can be a computer, or any other device such as a printer

– Every node has a unique address to locate it on the network

What is a computer network?

Crack the case!

Sheela, a florist, has a computer and printer in her shop. She has used them

successfully to

– keep sales records

– produce bills and vouchers

Sheela now needs two more computers for two additional billing counters.

You are the best networking consultant in town!

Sheela asks you – does she need to network her computers?

Crack the Case!

Task I

Could we prepare a questionnaire for Sheela to answer?

Help Sheela arrive at the need for networking

The answers should lead us to a Yes or No for Networking. Recall the

‗Why‘ of networking.

Purpose Sheela’s Need

Resource Sharing Printer? Internet Connection?

Data Sharing Sales across counters

How do we Network?

Crack the Case!

Task II

Sheela has heard that there are two different ways that her network could

be set up, either as a ‗peer to peer‘ or as a ‗client - server‘ network.

Work with two other persons in your class to produce a short presentation

to describe the differences between ‘peer to peer’ and ‘client - server’

networks.

Client Server Model

A client places a request - service requester

A server responds to client‘s requests - service provider

Client Server Model

The client/server model is a form of distributed computing where one

program, the client, communicates with another program, the server, for the

purpose of exchanging information

Peer to Peer Model

A pure peer-to-peer network does not have the notion of clients or

servers, but only equal peer nodes that simultaneously function as both

"clients" and "servers" to the other nodes on the network.

Peer-to-peer is a communications model in which each party has the

same capabilities

How of Networking

How do I network?

Peer to PeerClient Server

Topology Physical Components Framework

Cables

Connectors

Devices

Reference Models

Addressing

LAN Technologies

Topology

The arrangement in which the nodes of a network are connected to each

other.

It is usually a schematic description of the arrangement of a network,

including its nodes and connecting lines

Topologies are either physical or logical

– The way that the workstations are connected to the network through

the actual cables that transmit data -- the physical structure of the

network -- is called the physical topology.

– The logical topology, in contrast, is the way that the signals act on

the network media, or the way that the data passes through the

network from one device to the next without regard to the physical

interconnection of the devices.

Common Topologies

Classification based on Topology

Bus Topology

– All computers are attached to a single continuous cable that is

terminated at both ends, which is the simplest way to create a

physical network

Terminator

Bus TopologyBus Failure

BusTopology.exe

BusFailure.exe

Star Topology

– Each computer is connected to a central point by a separate cable.

The central point is a device known as a hub

– Is much more fault tolerant than a bus topology. This means that if a

failure occurs along one of the cables connecting to the hub, only

that portion of the network is affected, not the entire network

– New nodes can be added by running a single new cable


Star Topology

StarTopology.exe

A

B

C

D

Ring Topology

– Each computer is connected directly to two other computers in the

network.

– Data moves down a one-way path from one computer to another in

a single direction only

Advantage:

– Laying the cables is relatively simple


Ring Topology

RingTopology.exe

Disadvantages of Ring Topology:

– A break in the cable results in the disruption of the entire network

– Adding new nodes can be tedious

– Since the data travels only clockwise, say, if machine A wants to

communicate with machine D, data can not be transferred if there is

a break in the loop


Failure of Ring Topology

RingFailure.exe

Mesh Topology – Fully Connected

– Each node of the network is connected to every other node with a

point –to-point link

– Makes it possible for a single node to communicate simultaneously

with all other nodes

Mesh Topology – Partially Connected

–Some nodes are connected to more than one other nodes through a

point-to-point link

–Reduces redundancy of the fully connected topology


Crack the Case!

Task III

Sheela is ready to proceed. You now need to research three different

network topologies (bus, ring and star) and extend the presentation you

prepared in Task II to describe the benefits and drawbacks of each one.

End your presentation with a recommendation to Sheela that includes

- The type of network topology and

- The reason behind the selection

Types of Computer Networks

Task III

Consider that Sheela now wants to go ahead and open a new store

altogether, away from the one that currently exists. If she wants to

network the two stores, what type of computer network should she be

looking for?

Classification based on Scale

LAN – Local Area Network

– A network that is limited to a relatively small area such as a room or

a single building

– Sometimes called a single location network

Linksys 33

MAN – Metropolitan Area Network

– A network that connects two or more LANs, but does not extend

beyond the boundaries or the immediate town or city


Chennai

Teynampet

Tambaram

Ambattur

T. Nagar

WAN – Wide Area Network

– Generally covers a relatively broader geographic area

– Usually uses transmission facilities provided by common carriers

such as telephone companies


Think Time

Basic models of networks discussed –

Peer to Peer

Client Server

Topologies discussed –

Based on physical connection –

Star, Bus, Ring and Mesh

Based on physical extent –

LAN, MAN and WAN

Do the above topologies apply to both the basic models – P to P and

Client Server?

LAN Technologies

Ethernet

Ethernet is the most common LAN (Local Area Network) technology in

use today.

The first Ethernet standard, 10Base-5, ran over thick coaxial cable.

A later standard, Ethernet 10Base-2, ran over a much thinner coaxial

cable.

These two versions of Ethernet were colloquially known as thicknet and

thinnet.

Ethernet Standard Cable Specification

10Base-T Category 3 UTP

100Base-TX Category 5 UTP

1000Base-T Cat 5e UTP

1000Base-SX Optical Fiber

Token Ring

A local area network (LAN) access method developed by IBM.

Conforming to the IEEE 802.5 standard, Token Ring uses a token ring

access method and connects up to 255 nodes in a star topology at 4, 16

or 100 Mbps.

All stations connect to a central wiring hub called the "Multistation

Access Unit" (MAU) using twisted wire cable.

Token Passing Token Ring Network

TokenPassing.exe

TokenRingNetwork.exe

Physical Components of a Network

Transmission Media

Fiber opticCoaxial Cable

1. Thicknet

2. Thinnet

Twisted pair

1. Shielded

2. Unshielded

Medium

Wired Wireless

A medium is a carrier of something

Coaxial Cable

Consists of a central copper core surrounded by an insulator, a braided

metal shielding, called braiding, and an outer cover, called the sheath or

jacket

High bandwidth – Up to 400 MHz

Max. used data rates – 100 Mbps

High quality of data transmission

Signal loss at high frequencies

Thicknet Coaxial Cable

Is a rigid coaxial cable approximately 1-cm thick used for the original

Ethernet networks

Also called ‗thick Ethernet‘, ‗yellow Ethernet‘ or ‗yellow garden hose‘

Usually found an older networks

IEEE designates Thicknet as ‗10Base5‘ Ethernet, interpreted as follows –

‗10‘ for transmission rate of 10 Mbps

‗Base‘ for baseband transmission

‗5‘ for the max. segment length of a Thicknet cable, which is 500 m

Thinnet Coaxial Cable

Popular medium used in Ethernet LANs in the 1980s

IEEE designates Thinnet as ‗10Base2‘ Ethernet, interpreted as follows –

• ‘10‘ for transmission rate of 10 Mbps

• ‗Base‘ for baseband transmission

• ‗2‘ for the max. segment length which is around 200 m

Thinnet

ThinEthernet.exe

Twisted Pair Cable

Consists of colour-coded pairs of twisted & insulated copper wires

Used extensively in telephone cables

Number of twists per unit length is known as ‗twist ratio’. More the

twist ratio, lesser the noise and therefore better the quality

Is inexpensive, flexible, and easy to install

One drawback to twisted-pair is that, because of its flexibility, it is more

prone to physical damage than coaxial cable

All twisted pair cables fall into two categories –

Shielded Twisted Pair (STP)

Unshielded Twisted Pair (UTP)

Twisted Pair Cables

Shielded Twisted Pair (STP)

– The insulated inner twisted pairs are surrounded by an additional

shielding usually made of metallic foil or braid

– The shielding acts as a barrier to external signals, thus reducing

noise

– The shielding may be grounded to enhance its protective effect

Unshielded Twisted Pair (UTP)

– Does not contain additional shielding

– Advantage over STP is that it is less expensive

– Absence of shielding, however, makes it more prone to noise

Straight Through Cable It is a type of UTP cable

The colour coding of the internal wires inside both ends of the cable are

similar

Straight through cables could be used to connect dissimilar devices like

Connecting a router to a hub or switch

Connecting a server to a hub or switch

Pin Number Wire color Wire Becomes Pin number Wire color

Pin 1 Orange / White

Pin 2 Orange

Pin 3 Green / White

Pin 4 Blue

Pin 5 Blue/White

Pin 6 Green

Pin 7 Brown/White

Pin 8 Brown

1 1

2 2

3 3

6 6

Pin 1 Orange / White

Pin 2 Orange

Pin 3 Green / White

Pin 4 Blue

Pin 5 Blue/White

Pin 6 Green

Pin 7 Brown/White

Pin 8 Brown

Crossover Cable

It is a type of UTP cable

The colour coding of the internal wires inside both ends of the cable are

dissimilar

Straight through cables could be used to connect similar devices like

Connecting hubs to switches

Connecting 2 hubs

Pin Number Wire color Wire Becomes Pin number Wire color

Pin 1 Orange/White

Pin 2 Orange

Pin 3 Green / White

Pin 4 Blue

Pin 5 Blue/White

Pin 6 Green

Pin 7 Brown/White

Pin 8 Brown

1 3

2 6

3 1

6 2

Pin 1 Green/White

Pin 2 Green

Pin 3 Orange/White

Pin 4 Blue

Pin 5 Blue/White

Pin 6 Orange

Pin 7 Brown/White

Pin 8 Brown

Straight Through vs. Crossover

The Transmit and Receive pins are shown above

Cross over cabling

CrossoverCabling.exe


Straight Through cable

Cross Over Cable


Similar Devices

Cross Over Cable

Dissimilar Devices

Straight through Cable

Hub / Switch PC

PCPC

UTP Types

Type Data Rate Usage

Cat 1 Up to 1 Mbps Telephone Line

Cat 2 Up to 4 Mbps Token Ring

Cat 3 Up to 10 Mbps Token Ring & 10 Base – T

Cat 4 Up to 16 Mbps Token Ring

Cat 5 Up to 100 Mbps Ethernet – 16 for Token Ring

Cat 5e Up to 1000 Mbps Ethernet

Cat 6 Up to 1000 Mbps Ethernet

IEEE Nomenclature

Standard Media Distance Connector

10 Base 2

10 Base 5

10 Base T

100 Base TX

Coaxial (Thinnet)

Coaxial (Thicknet)

CAT 3,4,5 UTP

CAT 3,4,5 UTP

185 M

500 M

100 M

100 M

BNC (British Naval

Connector)

AUI (Attachment Unit

Interface)

RJ 45 (Registered Jack – 45

Specific Wiring Sequence)

RJ 45

10 Base TTransmission rate Copper unshielded twisted pair

Base band signaling

Uses the entire bandwidth of

the transmission medium

Fiber Optic Cable Cables contain fiber lines in their cores instead of the usual copper wires

Technique uses light pulses to transmit information through these optic

fibers

Very high bandwidths of up to several Gbps

Could be used for long distances covering hundreds of kilometers

Provide very high bandwidth – up to 20, 000 MHz

Low interference provides highly efficient transmission

High costs are currently the only drawback

Media Dependent Interface X

Cross Over Cable

Straight through

Note: For uplink port Straight through and cross over cable can be used

Router Hub/Switch

Connectors

Coaxial Cable Connector

Registered Jack (RJ)

RJ-11 – Defined for

telephone connectors

RJ-45 – Defined for

UTP connectors

RJ 45RJ 11

Devices in Network

There are various network devices that are used to do networking.

They are

Repeater - Regenerates or replicates signals that are weakened or

distorted by transmission over long distances.

Hub - Regenerates signals and broadcasts it out all of their ports

Switch - Connects two or more network segments.

Bridge - Breaks larger network segments into smaller network

segments.

Routers - Connects different Subnets within a network or different

networks.

Framework of Networking

OSI (Open System Interconnect)

It is a reference model designed by International Organization for

Standardization (ISO) in 1974

OSI is a standard description for how messages should be transmitted

between any two points in a telecommunication network

Its purpose is to guide product implementers so that their products will

consistently work with other products

Physical Layer

Datalink Layer

Netword Layer

Transport Layer

Session Layer

Presentation Layer

Application Layer

The process of communication between two end points in a network can

be divided into layers, with each layer adding its own set of special, related

functions

Each communicating user or program is at a computer equipped with

these seven layers of function

So, in a given message between users, there will be a flow of data through

each layer at one end down through the layers in that computer and, at the

other end, when the message arrives, another flow of data up through the

layers in the receiving computer and ultimately to the end user or program

OSI (Open System Interconnect)

The Physical layer defines all the

electrical and physical specifications for

devices

Physical Layer defines techniques to

transfer bit stream to cable

Physical Layer

Hub and

Repeater

work in this

layer

ABC 0100111

Physical Layer

0100111 ABC0100111

Physical Layer

Physical Layer

Datalink Layer

Netword Layer

Transport Layer

Session Layer

Presentation Layer

Application Layer

Data Link Layer receives end packages

raw data from the Physical layer into data

frames for delivery to the Network layer as

packets

Data link Layer is divided in to two layers:

LLC (Logical Link Control)

MAC ( Media Access Control)

Main function is Error detection Switch, Bridge

and NIC work

in this layer

Data Link Layer

Physical Layer

Datalink Layer

Netword Layer

Transport Layer

Session Layer

Presentation Layer

Application Layer

Data Link Layer

Logical Link Control (LLC):

Its functions include:

•The LLC works with the transport

layer by providing connection-

oriented and connectionless

services. It manages and creates

the communication link.

•It uses a calculated value called

CRC to check and thus control the

errors occurred during the

transmission of the bits across the

wire

Media Access Control:

The MAC sublayer has two

primary responsibilities:

•Data encapsulation, including

frame assembly before

transmission, and frame

parsing/error detection during and

after reception

•Media access control, including

initiation of frame transmission

and recovery from transmission

failure

Physical Layer

Datalink Layer

Network Layer

Transport Layer

Session Layer

Presentation Layer

Application Layer Network Layer is responsible for providing best

path for data to reach the destination

Logical addressing is happening in this layer

Network Layer translates logical network address

and names to their physical address (e.g. computer

name = MAC address)

Internet Protocol is an example of Network Layer

protocol

Router works

in this layer

Network Layer

Transport Layer is responsible for reliable

delivery of data and error correction

Provides acknowledgment of successful

transmissions; requests retransmission if some

packets don‘t arrive error-free

Identifying Service, Multiplexing & De-

multiplexing and Segmentation happen in this

layer

Examples of transport layer protocols

Transmission Control Protocol

User Datagram Protocol

Brouter and

Gateway works

in this layer

Transport Layer

Physical Layer

Datalink Layer

Netword Layer

Transport Layer

Session Layer

Presentation Layer

Application Layer

Data

Breaking data into segments

This happens in the Transport Layer

Session Layer is responsible for

establishing, maintaining and

terminating session

Responsible for name recognition

(identification) so only the designated

parties can participate in the session

Manages who can transmit data at a

certain time and for how long [Dialog

Control]

Provides synchronization services by

planning check points in the data stream

if session fails, only data after the most

recent checkpoint need be transmitted

Gateway works

in this layer

Session Layer

Physical Layer

Datalink Layer

Netword Layer

Transport Layer

Session Layer

Presentation Layer

Application Layer

The Presentation layer transforms data to

provide a standard interface for the

Application layer

The Presentation layer relieves the

Application layer of concern regarding

syntactical differences in a message's data

representation within the end-user systems

Following tasks are performed in

Presentation Layer

Encoding – Decoding

Encryption – Decryption

Compression – Decompression

Gateway works

in this layer

Presentation Layer

Physical Layer

Datalink Layer

Netword Layer

Transport Layer

Session Layer

Presentation Layer

Application Layer

The Application layer provides a means for

the user to access information on the network

through an application

This layer is the main interface for the

user(s) to interact with the application and

therefore the network

Examples of application layer protocols

Telnet

File Transfer Protocol (FTP)

Simple Mail Transfer Protocol (SMTP) and

Hypertext Transfer Protocol (HTTP)

Gateway works

in this layer

Application Layer

Physical Layer

Datalink Layer

Netword Layer

Transport Layer

Session Layer

Presentation Layer

Application Layer

Computer B

6. Presentation

5. Session

4. Transport

3. Network

2. Data Link

1. Physical

Picture on web browser

Encoded picture

(JPG)

Initiates communications

(HTTP)

Communication PC to PC

(TCP)

IP Address assignment

Network Interface

(NIC)

7. Application

6. Presentation

5. Session

4. Transport

3. Network

2. Data Link

1. Physical

Picture on web browser

Encoded picture

(JPG)

Initiates communications

(HTTP)

Communication PC to PC

(TCP)

IP Address assignment

Network Interface

(NIC)

. . . 010100110

Layers Layers

Computer A

7. Application010100110

Communication between two computers

OSI Model

Gateway

HUB

Switch

Router

Data Travel in OSI

Data Encapsulation

DataEncapsulation.exe

Protocol

A Protocol is an agreed-upon format for transmitting data between two

devices. The protocol determines the following:

the type of error checking to be used

data compression method, if any

how the sending device will indicate that it has finished sending a

message

how the receiving device will indicate that it has received a message

Protocol suite is a compilation of many such protocols combined to

perform a set of tasks together and enable efficient communication over the

network.

TCP/IP Protocol Suite

The TCP/IP Protocol Suite, is a layered abstract description for

communications and computer network protocol design

It was built on the OSI Reference Model

Comparing OSI and TCP/IP

Although some of the layers in the TCP/IP model have the same name as

layers in the OSI model, the layers of the two models do not correspond

exactly.

Addressing

Just as we use postal address, email address to communicate with our

friends, we do need an address to identify our computer in this web of

network.

There are two different ways of identifying our machine in a network.

MAC address and

IP address

MAC Address

The Media Access Control address (MAC) can be equated to the serial

number of the NIC. Every IP packet is sent out of your NIC wrapped

inside an Ethernet frame which uses MAC addresses to direct traffic on

your locally attached network

MAC addresses therefore only have significance on the locally

attached network. As the packet hops across the Internet, its

source/destination IP address stays the same, but the MAC addresses

are reassigned by each router on the way using a process called ARP

MAC Address

MAC addresses are usually written in one of the following two

formats:

00:13:21:0F:83:DF 00-13-21-0F-83-DF

MAC address is a 48 bit address

MAC address are 12 digit Hexadecimal {0-9} {A- F} Address

The First Octet of the MAC Address is known as Group Unique -

00 : 13 : 21 : 0F : 83 : DF

The Second and Third Octet of the MAC Address is known as

Organization Unique Identifier (OUI) –

00 : 13 : 21 : 0F : 83 : DF

MAC Address

Any MAC address starts with 00 is known as Unicast address

00 : 13 : 21 : 0F : 83 : DF

Any MAC address starts with 01 is known as Multicast

01 : 13 : 21 : 0F : 83 : DF

Any MAC address starts with FF is known as Broadcast

FF : 13 : 21 : 0F : 83 : DF

MAC Address

MAC Address

Start Run Type winipcfg

For Windows 95, 98 & Me

Checking MAC Address

Select the Adapter

MAC Address



Click Start RunType cmd or command

For Windows 2000 & XP


Click Start Run Type cmd or command Type ipconfig /all

MAC Address

For Windows 2000 & XP


Type ipconfig / all

For Windows Vista


Internet Protocol Address is given to the computer as an identifier to a

computer in a TCP/IP Network

IP Address is also known as Logical Address

IP Address works in Layer 3 (Network)

Two versions of IP Addressing

IP Version 4 - 32 bit address (used currently)

IP Version 6 - 128 bit address

IP Address

To make it easier to work with these addresses, the 32-bit binary

number is broken into a series of decimal numbers.

To do this, split the binary number into four groups of eight binary

digits.

Then convert each group of eight bits, also known as an octet into its

decimal equivalent.

IP Address

Guna Complex, 6th Floor

Floor No.Building

Just as a street address has a standard two-part format (a street name and a

house number), each IP address is separated internally into two parts—a

network ID and a host ID

Parts of an IP Address

196 . 168 . 1 . 23

Network ID Host ID

Network ID:

The network ID, also known as a network address, identifies a single

network segment within a larger internetwork

All the systems that attach and share access to the same network have a

common network ID within their full IP address

This ID is also used to uniquely identify each network within the larger

internetwork

Host ID:

The host ID, also known as a host address, identifies a node within each

network

The host ID for each device identifies a single system uniquely within its

own network

Parts of an IP Address

IP Address is classified into three classes as follows

– Class A is written as N.H.H.H

– Class B is written as N.N.H.H

– Class C is written as N.N.N.H

Classification of IP addresses

• Class A 1 to 126

• Class B 128 to 191

• Class C 192 to 223

• Class D 224 to 239

• Class E 240 to 254

Widely Used

Multicast

Research & Development


Class First

Bits

First Byte

Values

Network ID

Bits

Host ID

Bits

Number of

Networks

Number of

Hosts

A

B

C

0

10

110

1 - 126

128 -191

192 - 223

8

16

24

24

16

8

126

16,384

2,097,152

16,77,214

65,534

254

IP Address Classes in a Nutshell

Click Start Select Run Type winipcfg Select the Adapter

Windows 95, 98 and Me

Checking IP Address

Start Run cmd or command ipconfig

For Windows 2000, XP

Checking IP Address

There is no Start button in Vista instead

it is Windows Logo

Type cmd in the Start Search drop

down box

Checking IP AddressFor Windows Vista

Command Prompt Window

Type ipconfig

For Windows Vista

Checking IP Address

Pull the Apple Menu

Select ‗System Preferences‘

Click the network Icon

For Mac OS X

Checking IP Address & MAC Address

Select TCP/IPSelect

using

DHCPIP Address

Mac Address

For Mac OS X


Select the Go menu Select Applications

Click Utilities

For Mac OS X


Select Ethernet

Select

DHCP

IP

Address

Default Gateway

Checking IP Address

For Mac OS 9

Think Time

What does the marked area stand for in the following screen

shot?

MAC Address

Think Time

Identify the MAC address & IP address in the following screen

shot -

MAC Address – 00 : 11 : 11: B2 : DA : CD

IP Address – 192 . 168 . 1 . 1

Think Time

What is the difference between MAC and IP address?

Do you know how you can find your MAC address using

some command as you do with IP address?

getmac

A ‗subnet‘ is a portion of the computer network that shares a common

address component

Dividing a network into subnets is useful for both performance and

security reasons

A ‗subnet mask‘ is used to determine what subnet an IP address

belongs to

Subnet Mask

Subnet Masking

Subnet_Masking.exe

Subnet Mask is to differentiate the Network ID and Host ID

Two numbers reserved for Subnet Mask i.e. 0 & 255

0 Denotes Host and 255 Denotes Network

Class Default Subnet Mask

Class A is written as 255.0.0.0 N.H.H.H

Class B is written as 255.255.0.0 N.N.H.H

Class C is written as 255.255.255.0 N.N.N.H

Subnet Mask

IP Address : 10.20.50.26 Subnet Mask : 255.0.0.0

For this IP Address :

Network ID is : 10.0.0.0

First Valid IP Address : 10.0.0.1

Last Valid IP Address : 10.255.255.254

Broad Cast Address : 10.255.255.255

Number of hosts = (256x256x256) -2

Subnet Mask

IP Address 172.26.28.36 Subnet Mask : 255.255.0.0

For this IP Address,

Network ID is :

First Valid IP Address :

Last Valid IP Address :

Broad Cast Address :

Number of hosts =

172.26.0.0

172.26.0.1

172.26.255.254

172.26.255.255

(256x256) – 2

Subnet Mask

For this IP Address:

Network ID is : 192.168.0.0

First Valid IP Address : 192.168.0.1

Last Valid IP Address : 192.168.0.254

Broad Cast Address : 192.168.0.255

Number of hosts = (256) – 2

IP Address 192.168.0.152 Subnet Mask 255.255.255.0

Subnet Mask

Private –

– A set of IP addresses reserved by the Internet Standards group

for private usage. It provides high security to the network.

Public

– All the other IP addresses come under Public IP addresses, which

can be easily accessed by everyone.

Static

– An IP address that remains the same every time the computer

logs on to the Internet.

Dynamic –

– Is assigned to a computer every time it connects to the Internet

and is different every time.


IP addresses can be -

IP addresses are publicly registered with the Network Information Centre

(NIC) to avoid address conflicts

Computers on private TCP/IP LANs however do not need public

addresses

For this reason, the NIC has reserved certain addresses that will never be

registered publicly. These are known as private IP addresses

The Internet Assigned Numbers Authority (IANA) has reserved the

following three blocks of the IP address space for private internets (local

networks):

10.0.0.0 - 10.255.255.255

172.16.0.0 - 172.31.255.255

192.168.0.0 - 192.168.255.255

Private IP Address

Class Network Address

A 10.0.0.0 through 10.255.255.255

B 172.16.0.0 through 172.31.255.255

C 192.168.0.0 through 192.168.255.255

Private IP Address Range

Private IP Address

Think Time

Please look into your terminals

Classify the IP addresses into Private and Public

Static IP Address

A permanent IP address that is assigned manually to a computer in a

TCP/IP network.

With a static IP address, other Internet users always know the identity of

the computer and can easily connect with it.

Start Run Type winipcfg Select the Adapter

Click Release

Assigning Static IP Address


Assign the IP address. After you have assigned the static

IP address you can never release or renew it



Click Properties

Select IP Address TAB Select TCP/IP



Select this Enter the IP address

Note: If assigning Static IP, Global DNS has to be assigned



Select ‗Internet Protocol

(TCP/IP)‘

Click Properties

Select ‗Use the following IP

Address‘

Note: For static IP, Global DNS must be assigned


For Windows 2000, XP

Assigning Static IP address

Go to Network Connection

Status & select Properties

Click Continue

Contd.

For Windows Vista

For Windows Vista


Select Use the following IP address Click OK

For Windows Vista


Type ipconfig to check the IP address

For Windows Vista


Assigning static IP Address

Type drakconf Select Network & Internet Manage connections

For Mandrake Linux

Select TCP/IP Select Static

For Mandrake Linux

Assigning static IP Address

Think Time

• Assume we have 100 computers networked as a LAN. Each

computer should be assigned an IP address.

• Do you think this task can be done manually?

• What are the possible difficulties or issues that might arise

here?

Dynamic Addressing

A temporary numeric identification assigned to a node in a TCP/IP

network.

ISPs typically assign dynamic addresses to the Internet connections of

their residential and small business customers, which are less expensive

than static addresses.

That means the IP address to the outside world in a cable or DSL

modem may change every month, every day or even every hour

When computers and devices in the network are turned on, they are

assigned an IP address by a DHCP server.

Releasing an IP Address

Start Run winipcfg

Select the Adapter

Click Release


Start Run winipcfg Select the adapter

Click Renew

Renewing an IP Address


Loopback Address

Loop Back Address:

The IP address 127.0.0.1 is used as the loop back address.

This means that it is used by the host computer to send a message back to

itself. It is commonly used for troubleshooting and network testing

Loopback Address

Loop Back address is also known as semi broad cast address

Range of Loop back address : 127.0.0.1 to 127.255.255.254

Any IP address starts with 127 is known as loop back address

Click Start Run Type cmd Ping 127.56.26.36

Type ping 127.0.0.1 and press Ctrl+z to stop the utility

For Mandrake Linux

Loop Back Address Test

Broadcast Address

Messages that are intended for all computers on a network are sent as

broadcasts

These messages always use the IP address 255.255.255.255

Any IP Address with last Octet as 255 is known as broadcast address for

that particular network E.g.: 10.255.255.255

The IP address of 0.0.0.0 is used for the default network

Think Time

Please look into your terminals

Match the IP addresses with their corresponding names

IP configuration - Error

The error message ‗The operation failed as no adapter is in the state

permissible for this operation.‘, indicates that static IP is assigned to

the computer and therefore can not be released

Error Message – IP release

Windows IP Configuration - Errors

If the network card is disabled the computer will display the

message ‗Windows IP Configuration‘ when you enter the

command ipconfig

If TCP/IP is unchecked, the computer will display the message

Windows IP Configuration, when you type the command ipconfig

Note: You cannot uninstall TCP/IP in Windows XP

Windows IP Configuration - Errors

Media Disconnected Error

If the network cable is unplugged or any damage in the cable the

command prompt window will display as media disconnected if we type

ipconfig. This is applicable only for Windows XP.

Cable Disconnected Error

If the network cable is unplugged or any damage in the cable the

command prompt window will display as cable disconnected if we type

ipconfig. This is not applicable for Windows XP.

Think Time

I have connected a PC to a hub/switch. I type ipconfig in the command

prompt. What will be the IP address? What will I get if I release /renew

the IP address?

Solution

If the static IP is assigned to the PC, then IP address will be displayed if

you type ipconfig. If no IP address has assigned to the PC the result will

be 0.0.0.0. If you try to release and renew the IP address will be 0.0.0.0

1. I have a desktop which uses Win98. I have installed a Linksys fast

Ethernet adapter. When I type winipcfg, I do not find the Linksys

adapter listed in the IP configuration window. What is the problem?

2. I have plugged the Linksys NIC card in the PCI slot. After I restart my

PC, I do not get found new hardware message. What troubleshooting

should I do?

Think Time

Ping

Ping is a utility used to check IP

connectivity between two hosts

Ping command works based on

Internet control message

protocol (ICMP)

Ping stands for Packet Internet

Gopher

Ping test

Click ‗Start ‗Run‘ Type ‗cmd‘ or ‗command‘ Type ping

<host name>

Loop back address test

Click ‗Start‘ ‗Run‘ Type ‗cmd‘ Type ‗ping 127.0.0.1 ‗

Note: 127.X.X.X is used for loop back address

Continuous pingType ‗ping <host name> –t ‗ in the command prompt

To stop continuous ping press Ctrl+C

Note : Ping 127.X.X.X is to check whether TCP/IP bindings installed properly. This command is not to check NIC card is working properly or not

Note : Ping 127.X.X.X, Ping localhost and Ping loopback are the same

Continuous ping

Select ‗Network Utility‘

Select Ping Tab

Click ‗Ping‘

Performing Ping Test

For Mac OS X

Trace Route

Trace route is a utility that shows you the route through the Internet

between your computer and a specified destination computer. Also it

displays the amount of time each hop takes. Trace route is a handy

tool to find out where problems may lay along the path between one

computer to another

Maximum Number of Hop Count displayed is 30

It also shows the response times in milliseconds for each hop

To perform a trace route the following command should be typed in

the command prompt as ―tracert‖ followed by website address

Performing Trace Route

Click ‗Start‘ Run Type ‗command‘ Type ‗tracert <host name>‘

For Mac OS X


Select the ‗Apple‘ Menu

Click Control Panel

Select TCP/IP


Latency

The amount of time it takes a packet to travel from source to destination.

Together, latency and bandwidth define the speed and capacity of a

network

Packet

Latency

My PC

Intranet Site

Website

ms = Millie Second

Latency can be found using the ―Ping‖ command

Time To Live (TTL)

It determines the maximum amount of time an IP packet may live in the

network without reaching its destination

It is effectively bound on the number of routers an IP packet may pass

through before being discarded

The ―Ping‖ and the ―Traceroute‖ utilities both make use of the TTL value

to attempt to reach a given host computer or to trace a route to the host

Address Resolution Protocol

Address Resolution Protocol is a TCP/IP protocol used to convert an IP

address into a physical address (MAC Address)

A host wishing to obtain a physical address broadcasts an ARP request

onto the TCP/IP network

The host on the network that has the address in the request then replies

with its physical hardware address

ARP belongs to Layer 3

192.168.2.28192.168.2.36

IP: 192.168.2.36 = ???

I need the

Ethernet address

of 192.168.2.36


MAP IP = MAC Address

192.168.2.28

IP: 192.168.2.36 = Ethernet : 00-16-17-18-42-8A

192.168.2.36

IP: 192.168.2.36 = ???

I heard that broadcast.

The message is for me.

Here is my Ethernet

address

I need the

Ethernet address

of 192.168.2.36


ARP Table


Used by a host to discover its IP address

A protocol, which provides the reverse function of ARP

RARP belongs to Layer 3

RARP is used to resolve an IP address from a given hardware address

(MAC address)

Reverse Address Resolution Protocol

Ethernet: 00-16-17-18-42-4B IP = ???

What is

my IP

address?


Map MAC = IP address

Ethernet: 00-16-17-18-42-4B = IP: 192.168.2.56

Ethernet: 00-16-17-18-42-4B IP = ???

What is

my IP

address?

I heard that

broadcast.

Your IP

address is

192.168.2.56


DNS (Domain Name System)

DNS is an internet service that translates domain name

(www.slashsupport.com) to IP Address

Internet is based on IP Address whereas domain names are

alphabetic, every time you use an domain name, DNS translates in to

corresponding IP Address

For example www.slashsupport.com to 216.148.62.220

DNS Name Resolution

DNSnameresolution.exe

.com .edu

.gov .org

DNS Name Resolution

.co

m

yahoo.com

google.com

msn.com

css.com

espnstar.com

www.msn.com

Web Server

Web ServersRoot Servers

www.msn.comRequest type

Web server

Root Server

207.68.172.246

PC connected to Internet sending a request to website www.slashsupport.com

DNS Server -

resolves domain

name to

IP Address

www.slashsupport.com

resolved to IP

216.148.62.220

DNS

Note : If the IP address is dynamic, will be able to get the same webpage next time

DNS

How to check DNS functionality?

The ―nslookup‖ tool to look up information in the DNS. Basically DNS

MAPS domain names in to IP addresses

To resolve an IP address in to domain name and domain name in to IP

address ―nslookup‖ command is used.

Select the adapter and click ‗More Info‘

Checking DNS


Assigning Global DNS

Select TCP/IP Select Enable DNS


Click Add Click OK


For Windows 95, 98 & Me (contd.)

On clicking ‗OK‘ the user is prompted to restart the computer

Assigning Global DNSFor Windows 95, 98 & Me (contd.)

Note: If the Host name is not entered the above error message appears on clicking

‗OK ‗.


For Windows 95, 98 & Me (contd.)

Flushing the DNS

When a computer visits a website for the first time, it stores the

website's DNS information in DNS cache

The next time the computer visits a website, it looks in the cache to

see if the website's information is present to use

This can cause problems if the website's DNS information has

changed since the computer's last visit

Flushing the cache removes all the information stored in cache,

forcing the computer to find the new DNS information for the

website

Flush and Register DNS

Type ipconfig /flushdns

Type ipconfig /registerdns

Think Time

A customer wants to assign global DNS in his computer. He

particularly requests for written instructions. Can we think of

minimum number of simple, and short steps?

Lets get together in groups!

Windows Internet Naming Service (WINS)

192.168.2.26

192.168.2.28

192.168.2.56

192.168.2.57

9C26

9C28

9C56

9C57

IP AddressHost Name

Local Machine (LM) host

IP : 192.168.2.26 IP : 192.168.2.28 IP : 192.168.2.56 IP : 192.168.2.57

WINS Server

9C26 9C28 9C56 9C57

9C26 trying to reach 9C56

WINS used in Intranet

WINS Server IP : 192.168.2.100

Errors while ‗Ping‘ing

Request Timed Out

The ping command timed out because there was no reply from the

host. The source and the destination computer are in the same network

When Ping command is initiated from one system to the other in a

network if the firewall is enabled on the Destination System Request

Timed Out error will Pop up

Destination Host Unreachable

This error occurs when the host that is pinged is in a different network.

Destination and the source belong to the different network

Request timed out vs. Destination Host Unreachable

IP : 192.168.1.53

Mask : 255.255.255.0

D.G : 192.168.1.1

IP : 192.168.0.8

Mask : 255.255.255.0

D.G : 192.168.0.1

IP : 192.168.2.56

Mask : 255.255.255.0

IP : 192.168.1.36

Mask : 255.255.255.0

Hub/Switch

Hub/Switch

Destination Net Unreachable

Destination Net Unreachable message is one which a user would usually

get from the Default Gateway when it doesn't know how to get to a

particular net work

Destination Host Unreachable vs. Destination Net Unreachable

Cable/DSL Modem

WAN Side

LAN Side

Internet

Note: Since the Router is not able to pass the WAN interface it

is giving the reply from LAN interface

IP : 192.168.2.168

Mask : 255.255.255.0

IP : 192.168.1.192

Mask : 255.255.255.0

Hub/Switch

Router

Unknown Host

If the DNS resolution is not happening the computer will display as

Unknown host

Global DNS has to be assigned to fix this issue

Command Prompt Error

If the static IP Address is assigned to the computer and if we tried to renew

the IP Address it will display as ―Operation failed as no adapter is in the state

permissible for this operation‖

Some Error Codes

Direct Firewall or PIX or Norton Internet Security Installed (NIS)

Error Code 28 (Command Prompt)

Anti Spy Ware or Zone Alarm in the Computer

Error Code 65 (Command Prompt)

networking basics

Education